PokePark 2: Wonders Beyond: Befriend Psyduck
Q: How do I befriend Psyduck?
A: Show Psyduck a picture of Emolga.

Psyduck says he's looking for a Pokemon that likes Hide and Seek and "has membranes on his arms..." Psyduck is looking for Emolga. Emolga is located in a crevice near Drilbur in Seasong Beach. Pass by Watchog and go up the ledge to find Emolga near a tree. If you already have Emolga as a friend you can find him walking around the beach near Drifblim and the water fountain.